Default colormaps for variables

[Dooruk]

We could (and should!) use a colormap package in EVA for visually striking plots. What's the proper way of implementing such feature, through EMCpy or EVA?. We could set defaults for different variables, something like this:

https://github.com/NOAA-EMC/emcpy/blob/develop/src/emcpy/cfg/var_defaults.yaml

Here is a popular colormap package option:
https://matplotlib.org/cmocean/